Ok, sorry to post this again, but I think my old one got deleted. I see on the Honduh's turbo kits, check valves are a nessicity. Anyways, where exactly on the turbo kits (hahn's or star's) are the check valves suppose to be? and what are there purposes? Obviously it's not to let air be sucked in but can someone explain this to me in detail? I know that there is one off the adjustbale FPR...anywhere else where this is a MUST HAVE?

umm..maybe the vacuum line from the wastegate to the turbo? since I just have a reg. vacuum line there will the boost be set to whatever the actuator is set to?

what kit do you have?
the star kit has no check valves..
a check valve is a one way valve...let's air through in one dir

l e o n

on the star kit, they go between the map sensor and the manifold...they let the boost blow through them, so that the map sensor doesn't see any boost. It's a bad design and thats why pretty much everyone goes with a VC1 or some other kind of fuel cut defencer so that the map sensor doesn't freak the ECU out when it sees boost. Of course, if you have a 95, then your in luck, cus you don't need either of them...

jason
95 GS Turbo

I have never heard of a checkvalve being installed on an FPR.
I would imagine that would be really bad, since you are blocking
off the boost signal to the fpr.

Anyway, the checkvalves are installed on turbocharged cars in order for the MAP sensor to not see boost (anything above 1bar).
If you were to run turbo w/o checkvalves on a MAP sensor based system you would experience huge hesitation, and car might possibly stall.
checkvalves are installed inline to the map sensor (prior to).

Diagram:
--- = Vacuum line

Well On the HRC kit, it says that a check valve must be installed on the regulator's bleeder valve.

Also, which goes back to my other question. Will a regular vacuum line be ok from the actuator to the turbo or do i need a check valve there? Basically if my wastegate actuator is set at 8 lbs, it won't boost to infinity without a special vacuum line right?

Star kits from Wyatt (if not all) come with the VC1 standard. Dont know what Hahn calls its electronic device but I'm sure its not using check valves either. Like said by someone else check valves only purpose is to keep the MAP from seeing positive pressure from boost. If the PCM reads a MAP signal greater than zero boost its beyond the parameters of the PCM and it acts up (for lack of better term). The VC1 reduces voltage (the signal to the PCM from the MAP) to trick the PCM into not seeing the positive pressure. Your right, nearly every run-of-the-mill Honda turbo kit has a check valve to bleed off positive pressure to the MAP. I even saw an add for a billet check valves for hondas so they must be fairly common. It could be possible that both of these kits came with check valves at one point but I'm not sure.


Stan2gnt
Stan2va@aol.com
95 Talon ES-I-NOS but T soon!
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If your wastegate is set at 8psi the only safe way to boost any higher is to get the spring/kit from the wastegate manufacturer to set it higher or buy a boost controller. I guess you could call a manual boost controller a check valve, it functions in the same manner (although I have never heard one called that. I've heard it being called a bleeder valve).


Stan2gnt
Stan2va@aol.com
95 Talon ES-I-NOS but T soon!
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You too can have a never updated site complete with old info and dated pics!

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a check valve as some of you guys said is one way valve (so if you were to blow in it from one side the air will go throw, if you blow from the other side your face will turn blue and you won't be able to let any air go throw it from that side :)

MBCs are 2 kinds

bleeder kind (a good way to think of it, is to bring a rubber hose and plug shut one side of it and poke a hole in the middle of the hose, then blow from the other side) this is almost how a bleeder type MBC is, except the hole you poke in the hose is adjustable in the bleeder type MBC ( I mean if you were to unscrew MBC it will let more air go out from where it's bleeding from) almost like if you were to make that hole in the hose we were just talking about bigger which will allow you to bleed more air throw it.

the other kind is Ball and Spring kind except with this kind, you have a ball and spring inside the same unit, and this ball shuts the hole where it bleeds from untill there is enough pressure to move it a way from that hole so the MBC can bleed the air out.

a good example of a check valve is that little black thing connected to your valve cover from one side and your intake manifold from the other side (there is a hose in between tho) take it out and blow in one side, and try to blow from the other, now that is a check vavle.

Adel

LoL

Thanks for all the replies, but what if i really want to keep my boost level at the minimum amount that the wastegate is set for? Will a regular vacuum line be sufficient enough or do i need a MBC or a check valve?

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if you wanna keep the boost to the lowest setting (the same as your WG spring rate) then yeah a regular vacuum line going from the turbo or the intake manifold to your WG will do.

Adel